This project is directed to the discovery of a steroid for adjunctive treatment of androgen-dependent prostatic carcinoma which will act by interfering with dihydrotestosterone (DHT) economy at the enzyme and receptor levels. To this end, steroids designed as 5 alpha-reductase inhibitors and as androgen-receptor antagonists, respectively, will be synthesized and screened (1) in vitro for 5 alpha-reductase inhibiting activity, and for DHT-binding affinity and (2) in tissue culture models including human prostatic cancer preparations. Antiandrogenic and endocrine studies will be carried out as required.